These have been scrapbook seasons for Tom Hiddleston — over the last two years the 30-year-old British actor has worked with directors Steven Spielberg,Woody Allen, Kenneth Branagh, Terence Davies and Joss Whedon — but there is one snapshot memory from it all that he says "will be with me until the day I die." It was during the filming of "War Horse," the Christmas Day release that takes Spielberg back to the epic battlefields of Europe and puts Hiddleston in the saddle as Capt. Nicholls.

"There's a scene in the film where the British cavalry charge to the German front lines — and this is in the first world war, set in 1914 — 120 horses in formation, going full tilt, our swords gleaming in the sun," Hiddleston said, recalling the location shoot at the old Wisley Airfield in Surrey, England, in October 2010.

"It's this triumphant, martial moment, we were chasing the enemy through the German camp and into the wood. But what the British cavalry didn't know was that at the edge of the wood, waiting for them, is the first line of machine guns ever to be used in warfare. And there's a point when my character sees the machine guns and Steven wanted to do a simple close-up of my face at the very moment."

Hiddleston said the memorable aspect wasn't the thundering hooves, it was the advice that Spielberg gave him just before the camera captured that key close-up. "He said, 'How old are you, Tom?' I said, 'I'm 29.' He said, 'OK, I want your war face, the face you've been doing all day for all these battle scenes, all the hell fury. You're strong and courageous and you're 29. Then you see the guns and at that moment, I want you to de-age yourself by 20 years. You're a 9-year-old at that moment. I don't want you to do fear, I don't want fear or horror, I just want to strip away the man and see the boy.' It was the clearest and purest notes I had ever been given."

There are few people in cinema who understand the fragility and power of youthful wonder better than Spielberg, and that (along with those epic battlefields) has "War Horse" included in early Oscar conversations before most people have even seen it. The movie is based on the 1982 bestselling children's novel by Michael Morpurgo, but it was Nick Stafford's stage adaptation, which became a sensation with its use of equestrian puppets, that caught the attention of Spielberg's producing partner Kathleen Kennedy.

For the film, the horses are real (with the occasional spot help from the mechanical and digital variety), but the story is the familiar one of bravery, peril and heart-swelling devotion: A horse named Joey is separated from his beloved owner, Albert, and sold to the British officer played by Hiddleston, which begins the steed's extraordinary odyssey that will see him serve on both sides of the war even as Albert begins to search war-torn Europe in search of his lost friend.

Hiddleston said he loved the time on horseback, which was grueling physically but led to some sparkling moments and a bit of memorable praise from his Oscar-winning director. "He used to call me Errol Flynn if I got the take right," Hiddleston said with a sheepish grin. "He would just bellow from under the monitor tent, 'Errrolllll!' And, yes, I liked that."

"It's been a remarkable year because I've essentially worked with four or five cinema legends but all in very different parts. It never felt like I was excavating the same territory. I sometimes wonder if in fact I should be trying to present myself to the world with slightly more specific and unified things. But the actors I respect the most have always been shape shifters, and that's what I want to be."